What is vitamin D?

Vitamin D (calciferol) is a fat-soluble vitamin, that is, it is stored in the fatty tissues of the body. Vitamin D occurs naturally in some foods, is added to some foods, and is available as a supplement. Also, the ultraviolet (UV) rays of the sun shine on the skin, making vitamin D in the body.

Function of vitamin D in the body

Vitamin D promotes normal bone formation by increasing the absorption of calcium in the intestine and regulating the sufficient concentration of calcium and phosphate in the blood. This vitamin is essential for bone growth and regeneration. Vitamin D deficiency causes thin, brittle or deformed bones. Adequate vitamin D prevents rickets (a disease related to bone growth) in children and osteomalacia (soft bones) in adults. This vitamin along with calcium will protect the elderly from osteoporosis.

Vitamin D reduces inflammation in the body and improves processes such as cell growth, neuromuscular function, immune system and glucose metabolism.
Getting enough vitamin D helps keep us healthy by protecting against and helping to treat the following diseases:

Heart disease and high blood pressure: Vitamin D is important for cardiovascular health and normal blood pressure regulation. Some studies have shown that taking vitamin D supplements may help lower blood cholesterol levels and high blood pressure (two major risk factors for heart disease).
Diabetes: Vitamin D helps regulate blood sugar levels.
Infections and disorders of the immune system: Vitamin D has anti-inflammatory properties and regulates the immune system.
Falls in the elderly
Some types of cancer, such as colon, prostate, and breast cancer
Multiple Sclerosis (MS): A disease that affects the nerve cells that transmit messages from the brain to other parts of the body.

Absorption of vitamin D in the body

In foods and supplements, vitamin D exists in two main forms, vitamin D2 and vitamin D3, and both forms are well absorbed in the small intestine. The simultaneous presence of fat in the intestine increases the absorption of vitamin D.

Vitamin D deficiency

When the amount of vitamin D intake is lower than the recommended amount for a long time, people suffer from vitamin D deficiency.

Children who are deficient in vitamin D may have muscle weakness or pain.

In children, a severe deficiency of vitamin D manifests as rickets, this disease is characterized by a disturbance in the mineralization process of bone tissue, resulting in softening of the bones and deformation of the skeleton. In addition to bone deformities and pain, severe rickets can cause stunted or delayed growth, seizures due to low blood calcium levels, severe muscle cramps, heart problems, and dental malformations.

Long-term breastfeeding without the use of vitamin D supplements can cause rickets in infants.

Fortifying milk (as a good source of calcium) and other staple foods, such as breakfast cereals and margarine (vegetable butter), with vitamin D helps reduce the incidence of rickets.

Although vitamin D deficiency in adults is not necessarily symptomatic, if it has signs and symptoms, it includes the following:

tiredness
Skeletal pain
Muscle weakness, pain or cramps
Mood changes, such as depression

In adults and adolescents, severe vitamin D deficiency can lead to osteomalacia. In this disease, the bone regeneration process is done incompletely or defectively and as a result the bones become weak. The signs and symptoms of osteomalacia are similar to those of rickets, including bone deformity and pain, seizures due to low blood calcium levels, severe muscle cramps, and dental malformations.

Absorption of vitamin D in the body

Vitamin D deficiency

When the amount of vitamin D intake is lower than the recommended amount for a long time, people suffer from vitamin D deficiency.

Children who are deficient in vitamin D may have muscle weakness or pain.

Long-term breastfeeding without the use of vitamin D supplements can cause rickets in infants.

Fortifying milk (as a good source of calcium) and other staple foods, such as breakfast cereals and margarine (vegetable butter), with vitamin D helps reduce the incidence of rickets.

Although vitamin D deficiency in adults is not necessarily symptomatic, if it has signs and symptoms, it includes the following:

tiredness
Skeletal pain
Muscle weakness, pain or cramps
Mood changes, such as depression

Diagnosis of vitamin D deficiency

Checking the level of vitamin D is usually done with a blood test requested by doctors.

What people are at risk of vitamin D deficiency?

It is difficult to get enough vitamin D from natural (unfortified) food sources alone. Vitamin D deficiency is more likely in the following people:

Babies and infants:

Breast milk consumption alone is not able to meet the needs of vitamin D in infants.
Although exposure to UV rays can lead to vitamin D production in infants, exposing infants younger than 6 months to direct sunlight is not recommended. It is recommended to use 400 units (400 IU equivalent to 10 micrograms) of vitamin D supplement daily for infants.
Currently, in our country, for all children who are fed with breast milk or artificial milk, vitamin D is prescribed at a dose of 400 units (equivalent to 10 micrograms) from the 3rd to the 5th day of birth until the end of the 2nd year (24 months).

Seniors:

Due to the decrease in the skin’s ability to make vitamin D with age, the elderly are more at risk of vitamin D deficiency. In addition, the elderly spend more time at home than younger people and are more likely to be malnourished.

People who stay at home and people with jobs that limit sun exposure are among the groups that are unlikely to get adequate amounts of vitamin D through sunlight.

People with dark skin: more melanin pigment in the skin’s epidermis layer (the outermost layer of the skin) leads to skin darkening and reducing the skin’s ability to produce vitamin D from sunlight.
Patients with fat absorption disorder:
Since vitamin D is fat-soluble, its absorption depends on the intestine’s ability to absorb fat. Some types of diseases include disorders that cause malabsorption of fat, such as:

Liver disease
Cystic fibrosis (an inherited disorder that causes severe damage to the lungs and digestive system)
Celiac disease (an autoimmune disease that leads to gluten intolerance in a person)
Crohn’s disease (an inflammatory bowel disease)
Ulcerative colitis (another inflammatory bowel disease)

Obese people or people who have undergone gastric bypass surgery:
People with a body mass index (BMI) of 30 or more have lower blood levels of vitamin D than non-obese people.
Obese people who have undergone gastric bypass surgery may also suffer from vitamin D deficiency; Because in this method, part of the initial part of the small intestine, where vitamin D is absorbed, is bypassed.

Ways to prevent vitamin D deficiency

Since it is difficult for people to get enough vitamin D through diet, we should all consider taking vitamin D supplements to prevent vitamin D deficiency. In healthy people, the amount of vitamin D needed daily varies according to age.

Treatment of vitamin D deficiency

The goals of treatment and prevention of vitamin D deficiency are the same: to achieve and then maintain adequate levels of vitamin D in the body.

It is usually recommended to use vitamin D supplements to achieve this goal. To know the amount of vitamin D supplement needed, we should consult with our doctor.

Vitamin D sources

Food

Few foods naturally contain vitamin D. Fatty fish meat (such as salmon, salmon, tuna and mackerel) and cod liver oil are the best sources of vitamin D.
Beef liver, egg yolk and cheese have small amounts of vitamin D. Mushrooms provide varying amounts of vitamin D. The available evidence suggests that there is no significant difference in the ability to absorb vitamin D from different foods.
Foods enriched with vitamin D are a good source of this vitamin.

Exposure to sunlight

Most people get at least some of their vitamin D needs through sun exposure.

Season, time of day, length of day, cloud cover, air pollution, skin color, and use of sunscreen are among the factors that affect UV exposure and vitamin D production. Older people and people with dark skin are less able to produce vitamin D from sunlight. UVB does not penetrate glass, so exposure to sunlight indoors through a window does not lead to vitamin D production.

Some experts and researchers suggest exposing the face, hands, and feet without sunscreen for approximately 5 to 30 minutes in the sun, especially between 10:00 a.m. and 4:00 p.m., daily or at least twice. per week, usually results in adequate vitamin D production.

We must remember that ultraviolet rays are also carcinogenic and exposure to ultraviolet rays is the most preventable cause of skin cancer. To reduce the risk of skin cancer, protective measures are recommended, including using sunscreen with a sun protection factor (SPF) of 15 or higher whenever you are exposed to the sun.

supplements

Dietary supplements contain either vitamin D2 or D3, and both increase serum vitamin D levels and appear to be equally effective in treating rickets. However, most evidence suggests that vitamin D3 increases blood levels of vitamin D to a greater extent than vitamin D2.

Can vitamin D be harmful?

The answer is yes, taking too much vitamin D can be harmful.

Very high levels of vitamin D in the blood (greater than 150 ng/ml) can cause nausea, vomiting, muscle weakness, confusion, pain, loss of appetite, dehydration, increased urination, excessive thirst, and kidney stones. Very high levels of vitamin D can also lead to kidney failure, irregular heartbeat, and even death.

High vitamin D levels are almost always caused by taking too many vitamin D supplements; Because our skin limits the amount of absorbed vitamin D.

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